(1) Field of the Invention
The invention concerns a process for igniting a gas stream and a circuit arrangement for carrying out this process as can be used for a gas heating stove with gas regulator fittings.
(2) Description of Related Art
Facilities for a gas heating stove or the like are available in a large number of designs.
And so an ignition device for igniting gases is described in U.S. Pat. No. 5,722,823 A. The ignition device has a magnet coil that operates a gas valve, an igniter to ignite the gas stream electrically and a remote control that is connected to the magnet coil and the igniter via a low-voltage line. The remote control includes an energy supply and a time switch for timing the provision of low voltage.
This design requires a great deal of energy to ignite the gas stream. So there is provision for three relay coils, which means a relatively high power input. The solenoid valve is constantly energised during the ignition process, which results in a high power consumption. Consequently the only energy supply option is a mains supply. Another disadvantage is that faults occurring within the switch can lead to safety-related issues.
A valve device for controlling the ignition of a gas burner is familiar from the GB 2 351 341 A. An operating spindle is moved by hand into the ignition position, which opens the ignition locking valve. The operating spindle needs only be held a short time in this position as a microswitch is engaged when the operating spindle is moved. This causes a voltage to be made available from a power supply to engage the magnet. Ignition takes place by piezoelectric spark ignition. The power supply is switched off when the thermoelectric current provided by a thermocouple is sufficient to keep the ignition locking valve in its open position.
Even with this solution use of a power supply is a disadvantage. Additional effort is also needed to carry out the piezoelectric spark ignition. Especially where there is a fairly large conduction gap between the ignition locking valve and the burner aperture there is a further problem insofar as there cannot yet be any ignitable gas mixture at the burner aperture, as the time between the ignition locking valve opening and ignition is relatively short.
Further to this DE 93 07 895 U describes a multi-function valve with thermoelectric locking for gas burners on heating devices. This multifunction valve uses a room's existing power supply to operate it. To ignite the gas stream a magnetic valve is energised via a pushbutton, opening the ignition locking valve. The gas stream is ignited at the same time. A thermocouple in the area of the ignited gas flame is heated and puts a magnetic insert into an energised condition via the resultant thermoelectric current. The magnet holds an anchor firm and so keeps the ignition locking valve linked to the anchor in the open position. Now the pushbutton can be released and the magnetic valve be de-energised.
Here it is a disadvantage that the pressure valve must be held long enough until the thermoelectric current holds the ignition locking valve in the open position. It is also a disadvantage that the power consumption is relatively high in view of the fact that the magnetic valve must remain energised for this time via the power supply so that a mains supply is necessary.
Both solutions described in GB 2 351 341 A a in DE 93 07 895 U also have the disadvantage that they cannot be run fully automatically, and manual operation is necessary.